title: A spectrophotometric method for the estimation of polymer-supported sulfhydryl groups.
abstract: A sensitive and simple method is described for the quantitative determination of free sulfhydryl (-SH) groups on polymer supports. The method includes the reaction of 4,4'-dimethoxytrityloxy-S-(2-thio-5-nitropyridyl)-2-mercapto ethane (DTNPME) with polymer-supported sulfhydryl groups. After removal of excess reagent through washing, a weighed quantity of the polymer support is treated with perchloric acid to release the 4,4'-dimethoxytrityl cation from the polymer support into the solution. The dimethoxytrityl cation (lambda max = 498 nm, epsilon 498 = 70,000/M) is then quantified spectrophotometrically. A comparative study of the reagent DTNPME with 2,2'-dithiobis(5-nitropyridine) is also described.
authors.affiliation: Nucleic Acids Research Laboratory, CSIR Centre for Biochemicals, Delhi, India.
authors.forename: P
authors.initials: P
authors.lastname: Sharma
authors.forename: S
authors.initials: S
authors.lastname: Sathyanarayana
authors.forename: P
authors.initials: P
authors.lastname: Kumar
authors.forename: K C
authors.initials: KC
authors.lastname: Gupta
mesh_terms: D002846:Chromatography, Affinity / Q000379:methods; D011108:Polymers / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis; D013053:Spectrophotometry / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000032:analysis*; D014320:Triphenylmethyl Compounds / Q000138:chemical synthesis
chemical_list: D011108:Polymers; D011725:Pyridines; D013438:Sulfhydryl Compounds; D014320:Triphenylmethyl Compounds; C067106:4,4'-dimethoxytrityloxy-S-(2-thio-5-nitropyridyl)-2-mercaptoethane; C011801:2,2'-dithiobis(5-nitropyridine)